Method for fabricating interconnect structure

Abstract

Various embodiments provide interconnect structures and fabrication methods. A carbon-containing dielectric layer can be formed on a substrate. A protective layer can be formed on the carbon-containing dielectric layer to prevent carbon loss from the carbon-containing dielectric layer by performing a surface treatment to the carbon-containing dielectric layer using a gas at least containing silicon and hydrogen. A hard mask layer can be formed on the protective layer. A through hole can be formed in the carbon-containing dielectric layer using the hard mask layer as a mask to expose a surface of the substrate for forming a contact plug in the through hole.

What is claimed is: 
     
       1. A method for fabricating an interconnect structure, comprising:
 forming a carbon-containing dielectric layer on a substrate by treating a dielectric material on the substrate using ultraviolet (UV) light in a UV-treatment chamber, wherein the carbon-containing dielectric layer is made of a material consisting of SiCOH, SiCO, and SiCON; 
 forming a protective layer on the carbon-containing dielectric layer to prevent carbon loss from the carbon-containing dielectric layer by in-situ performing, in the UV-treatment chamber, a surface treatment to the carbon-containing dielectric layer using a gas at least containing silicon and hydrogen; 
 forming a hard mask layer on the protective layer using a non-oxygen plasma in a plasma-enhanced deposition to further prevent carbon in the carbon-containing dielectric layer from reacting with oxygen during the plasma-enhanced deposition; and 
 forming a through hole in the carbon-containing dielectric layer using the hard mask layer as a mask to expose a surface of the substrate for forming a contact plug in the through hole. 
 
     
     
       2. The method of  claim 1 , wherein the carbon-containing dielectric layer is a low-K dielectric layer or an ultra-low-K dielectric layer. 
     
     
       3. The method of  claim 1 , wherein the carbon-containing dielectric layer is formed by a diethoxymethylsilane and atom transfer radical polymerization. 
     
     
       4. The method of  claim 1 , wherein the protective layer is made of a material including C, Si, H, O, or a combination thereof. 
     
     
       5. The method of  claim 1 , wherein the gas containing silicon and hydrogen includes silane. 
     
     
       6. The method of  claim 5 , wherein the performing of the surface treatment to the carbon-containing dielectric layer includes using silane and helium. 
     
     
       7. The method of  claim 6 , wherein the performing of the surface treatment using silane and helium includes:
 a silane concentration ranging from about 100 mg/m 3  to about 300 mg/m 3 ; 
 a helium flow rate ranging from about 2000 sccm to about 4000 sccm; 
 a high-frequency power ranging from about 300 W to about 600 W; 
 a low-frequency power ranging from about 150 W to about 250 W; and 
 a chamber pressure ranging from about 3 torr to about 8 torr. 
 
     
     
       8. The method of  claim 5 , wherein the performing of the surface treatment to the carbon-containing dielectric layer includes using silane and argon. 
     
     
       9. The method of  claim 8 , wherein the performing of the surface treatment using silane and argon includes:
 a silane concentration ranging from about 100 mg/m 3  to about 300 mg/m 3 ; 
 an argon flow rate ranging from about 1000 sccm to about 2000 sccm; 
 a high-frequency power ranging from about 300 W to about 600 W; 
 a low-frequency power ranging from about 150 W to about 250 W; and 
 a chamber pressure ranging from about 3 torr to about 8 torr. 
 
     
     
       10. The method of  claim 1 , wherein the plasma-enhanced deposition for forming the hard mask layer includes a plasma-enhanced tetraethyl orthosilicate (PETEOS) deposition. 
     
     
       11. The method of  claim 1 , wherein the hard mask layer is made of a material including silicon oxide. 
     
     
       12. The method of  claim 1 , wherein the forming of the through hole in the carbon-containing dielectric layer includes a wet etching using a diluted hydrofluoric acid. 
     
     
       13. The method of  claim 1 , wherein the carbon-containing dielectric layer is made of black diamond.